--- a/bin/isabelle_java	Wed Oct 19 16:01:07 2022 +0200
+++ b/bin/isabelle_java	Thu Oct 20 14:59:39 2022 +0200
@@ -64,7 +64,7 @@
     exit 127
   else
     unset ISABELLE_HOME
-    unset CLASSPATH
+    export CLASSPATH=""
     exec "$JAVA_HOME/bin/java" "${JAVA_ARGS[@]}" \
       -classpath "$ISABELLE_CLASSPATH" "$@"
   fi